Laser 'un-printing' wipes ink from paper

There is a lot of talk about approaching a paperless office thanks to mobile devices in the workplace, but until that day comes, the humble sheet of A4 will continue to reign supreme in offices across the world.

This, of course, has its down sides. The vast swathes of forest-devouring paper that are produced for offices has an enormous environmental impact, both in terms of vanishing foliage and carbon emissions pumped out during recycling.

Certainly there are efforts to reduce the amount of wastage produced, and most offices are likely to have at least some form of reuse plan in place.

However, by cutting out the need to actually recycle paper at all, or at least severely limit it, a reduction of up to 80 percent of recycling emissions could be made, while trees would be left untouched.

Now, the University of Cambridge has developed technology which removes the toner from a piece of paper through the use of a laser, leaving a sheet of paper ready to be used again.  It is, effectively, a Tippex upgrade.

The team used a number of lasers along a range of strengths and pulse durations spanning a spectrum from ultraviolet to infrared.  They found that it was possible to totally remove the printed ink from the paper with little damage, allowing for immediate use.

This takes away the need for various time and energy consuming procedures that would be involved otherwise, such as forestry, pulping, paper making and disposal by incinerator, the researchers claim.

Currently, the team is on the lookout for a way to build a prototype device capable of performing the ‘un-printing’. However, they believe that the technology could well be present in offices across the country in the future, with tests showing that it works using your everyday Canon paper and HP Laserjet black toner.

According to one of the researchers, David Leal, there are a number of problems to be faced before we see machines in the workplace. “There are two challenges at the moment, speed and cost,” he told TechEye. “Both are directly related to the possibility of building a laser with the right specs for the process.

“A prototype would have a high initial cost because we are using specialised laser that have been designed for laboratory use in a niche market,” Leal said. “The challenge would be to design a cheaper laser and after this the cost could go down by economies of scale.”

Another hurdle is ensuring that a machine would be able to work on the full spectrum of ink types.

“The effectiveness depends on the toner-paper-laser setup combination,” Leal explained. “We have found a combination that gives very good results – no considerable mechanical and chemical damage to the paper, no discolouration of the paper, and leaves almost no traces of toner behind.

“The laser that we have identified as the best alternative is capable of removing a certain range of toners from paper, but it doesn’t work with every type of toner available in the market.

“In particular, it has trouble with certain types of yellow toners. So, in summary, it is effective for certain toner-paper combinations, but cannot be used universally.”

But, with the team looking to secure the £19,000 necessary to build a prototype, it is not clear how long development might take.

“We haven’t developed a timescale yet,” he said. “The first step would be to obtain the necessary funding to build a prototype and further develop the concept to overcome certain practical challenges such as cost and speed.

“After this it could be possible to talk with copier makers to see if we could license this idea.”